Gulf Keystone said its chief executive had agreed to transfer 17.4m shares to Ashley Kozel as part of a "confidential agreement" executed on January 12.

The settlement could hit the value of Gulf Keystone shares as Mrs Kozel's intentions over whether to sell up or retain ownership remain unclear. The shares fell 7.75 to 267.25p on Tuesday.

The company said: "As part of the divorce settlement the shares will be transferred to Mrs Kozel free and clear of any restrictions on their sale other than an orderly market condition on any resale."

The transfer means Mr Kozel has been left with less than 700,000 shares and options over a further 16.9m.

Gulf Keystone's shares have soared this year on speculation of a potential takeover bid and strong trading numbers. The Kurdistan-focused oil and gas explorer's shares are up 41.5pc this month, adding £14m to the value of Mrs Kozel's new stake.